The Dynamic Host Configuration Protocol (DHCP) is a network management protocol used on UDP/IP networks whereby a DHCP server dynamically assigns an IP address and other network configuration parameters to each device on a network so they can communicate with other IP networks.
Network address translation (NAT) is a method of remapping one IP address space into another by modifying network address information in the IP header of packets while they are in transit across a traffic routing device.
Port Address Translation (PAT), is an extension to network address translation (NAT) that permits multiple devices on a local area network (LAN) to be mapped to a single public IP address. The goal of PAT is to conserve IP addresses.
Site to Site VPN
A site-to-site VPN allows offices in multiple fixed locations to establish secure connections with each other over a public network such as the internet. Site-to-site VPN extends the company’s network, making computer resources from one location available to employees at other locations. An example of a company that needs a site-to-site VPN is a growing corporation with dozens of branch offices around the world.
There are two types of site-to-site VPNs:
- Intranet-based — If a company has one or more remote locations that they wish to join in a single private network, they can create an intranet VPN to connect each separate LAN to a single WAN.
- Extranet-based — When a company has a close relationship with another company (such as a partner, supplier or customer), it can build an extranet VPN that connects those companies’ LANs. This extranet VPN allows the companies to work together in a secure, shared network environment while preventing access to their separate intranets.
An access–control list (ACL), with respect to a computer file system, is a list of permissions attached to an object. An ACL specifies which users or system processes are grantedaccess to objects, as well as what operations are allowed on given objects. Each entry in a typical ACL specifies a subject and an operation.